DNS Record Types Cheat Sheet

If you’re new to DNS or don’t work with it on a daily basis, all the acronyms and terms can make you feel like you’re looking at “Matrix” code. DNS record types are no exception. But don’t worry, you can go ahead and take the red pill. Think of us as your Morpheus. We’re here to help guide you through the complexities of the DNS world.

DNS records are essentially instructions created by and stored on DNS servers in what is called a Zone File. These records provide important and relevant details about domains and hostnames. It might be helpful to think of them as business listings or directories. These “listings” help DNS servers direct queries to where they need to go.

Some of the information included in DNS records are the associated IP address, domain name, TTL (time to live), class (usually IN for internet), and type (A, AAAA, etc.).

One example of how this could look is: www.constellix.com. 1200 IN A [IP address]

In the cheat sheet below, you’ll find the most common DNS record types, what they stand for, and what purpose they serve. Be sure to bookmark this page so you’ll have it for easy reference anytime you need it.
“But I can only show you the door. You’re the one that has to walk through it.” — Morpheus (Laurence Fishburne), The Matrix. 1999

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A (address) — Most commonly used to map a fully qualified domain name (FQDN) to an IPv4 address and acts as a translator by converting domain names to IP addresses.

AAAA (quad A) — Similar to A Records but maps to an IPv6 address (smartphones prefer IPv6, if available).

CNAME (Canonical Name) — An alias that points to another domain or subdomain, but never an IP address. Alias record mapping FQDN to FQDN, multiple hosts to a single location. This record is also good for when you want to change an IP address over time as it allows you to make changes without affecting user bookmarks, etc.

ANAME — This record type allows you to point the root of your domain to a hostname or FQDN

SOA (Start of Authority) — Stores information about domains and is used to direct how a DNS zone propagates to secondary name servers.

NS (name server) — Specifies which name servers are authoritative for a domain or subdomains (these records should not be pointed to a CNAME).

MX (Mail eXchange) — Uses mail servers to map where to deliver email for a domain (should point to a mail server name and not to an IP address).

TXT (text) — Allows administrators to add limited human and machine-readable notes and can be used for things such as email validation, site, and ownership verification, framework policies, etc., and doesn’t require specific formatting.

SRV (service) — Allows services such as instant messaging or VoIP to be directed to a separate host and port location.

PTR (pointer) — A reverse of A and AAAA records, which maps IP addresses to domain names. These records require domain authority and can’t exist in the same zone as other DNS record types (put in reverse zones).

SPF (sender policy framework) — Helps prevent email spoofing and limits spammers.

DNS RECORD TIP: Always check for typos and mistakes when entering your DNS record information, especially your IPs. The Zone Config File is a good place to check your work and spot any mistyped information.

Originally published at https://constellix.com.

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